Searching advertising is an important part of the Internet business marketization. Using the matching relevance between the questions searched by the Internet user and the keyword purchased by the advertiser, the search engine presents to the Internet user advertisings she might be interested in, and charges the advertiser a certain fee for the user's click on the advertising, thus achieving a win-win situation among the search engine, the Internet user and the advertiser. During this process, the keyword purchased by the advertiser is an important link connecting the three parties. Therefore, how to choose the right keyword is one of the basic questions for the many advertisers and the Search Engine Marketing (SEM) companies.
However, the existing keyword filtering method is usually based on the words purchased by the advertiser and calculates the literal relevance of the words to the candidate keywords as the relevance of the advertiser's business to the candidate keywords. However, this method has a low accuracy problem.